ROBs track the lifecycle of micro-operations and/or instructions. ROBs may track an instruction's allocation, execution, retirement, and/or data result. In traditional computer architectures, the size of the ROB had to be increased as the need for the number of instructions to be tracked in parallel increased. This approach, however, has many drawbacks. Namely, increasing the size of the ROB may severely impact circuit timing, area, and power usage due to the additional hardware necessary to support the size increase.